Seventeen people, including two journalists from France and the U.K., were arrested Thursday night in Bujumbura, deputy spokesman of the Burundian police said Friday.

Moise Nkurunziza, deputy spokesman of the Burundian police, told Anadolu Agency that French journalist Jean-Philippe Remy, who works for French daily Le Monde and British freelance photographer Phil Moore, were among those arrested.

"We were surprised to find two foreign journalists in the French and British among the armed criminals. It happens for the first time,” Nkurunziza said.

However, French Foreign Minister Laurent Fabius has called for the immediate release of the journalists.

"We learned with concern the arrest in Burundi of French journalist Jean-Philippe Remy, and the British photographer Philip Moore," Fabius said in a statement on Friday.

"I call on the Burundi authorities to proceed with their immediate release," he said, adding that "diplomatic measures are ongoing."

The spokesman of the Burundian president, Willy Nyamitwe, also confirmed the detention on his official Twitter account.

Thursday evening, a large police operation was carried out in two neighborhoods near the city center of Bujumbura, gripped by turmoil for nearly nine months.

The Foreign Correspondents' Association of East Africa, FCAEA, released a statement Friday and expressed its concerns over the detention.

“We are deeply concerned about them and are yet to hear the charges they were arrested on,” said the FCAEA. “All channels are being pursued for their timely release.”

Burundi has been gripped by instability since April when Pierre Nkurunziza announced that he would run for a third term as president.

He survived a coup attempt in May, and secured a third term in disputed elections in July. He has been in power since 2005.

According to the UN, at least 3,496 people have been arrested in relation to the political crisis in the country.

The worst spout of violence occurred on Dec. 11 when 87 people were killed in clashes in Bujumbura.

Over 218,000 Burundians are now refugees in neighboring countries within the East African region.